1. Field of the Invention
This invention pertains generally to imaging of tissues associated with skeletal joints. More particularly, it relates to identification and/or characterization of localized factors associated with musculoskeletal pain using labeled markers and related imaging tools.
2. Description of Related Art
Chronic back pain (i.e. generally persisting longer than 12 weeks) is among the most prevalent and expensive non-lethal conditions in the United States, and is believed to be the most common cause of disability in persons under 45 years old. The number of people suffering from chronic back pain is estimated to exceed 25% of the overall population. Every year, about 3-4% of the U.S. population is estimated to be disabled temporarily, and about 1% of the working age population is estimated to be disabled totally and permanently, due to intractable back pain. An estimated 11.7 Million patients present medically with chronic back pain. National disability expenses for this prevalent condition range from $30-$70 billion per year. Effectively treating this prevalent condition remains among the largest unmet clinical needs in medicine. Properly diagnosing and localizing the source of pain also remains a significant shortcoming on the critical path toward providing such therapy in a targeted manner with predictably successful outcomes.
Diagnosis of the location, mode, and extent of disc degeneration is often used as a precursor tool to drive therapy for treating back pain. However, such measures are often not specific enough to localize the exact site in or around a degenerating disc where pain is being experienced. Also, a direct correspondence is not always found between disc degeneration and back pain. Consequently, existing imaging modalities that identify (and even quantify) disc anatomy, such as CT or MRI, are not always helpful at localizing sources of back pain in many cases.
Accordingly, there is still a substantial need for new imaging modalities to objectively, accurately, and specifically identify and localize source(s) of pain, and in particular back pain, and still more particularly lower lumbar back pain. There is in particular such a need with respect to identifying painful discs in an improved way, and to localize within or around those discs the specific site of injury or source of pain in an improved, predictable, dependable manner.